Downloaded some megademos from ftp and most of them are split in half (to fit on PC floppys I guess). Stupid question maybe, but how do I combine them to one .dms to run in WinUAE? Mounting each half in DF0: and DF1: in WinUAE and copy tracks with X-Copy or something would take too much time I think

Strange that this works for you.
I always depack the two dms parts to adf-images and then join the adf files.
If you join two dms files you have the header of the second dms-file added in the middle of the joined file and at least the popular XDMS cannot depack those files!
Just tested: original amiga DMS can depack those joined dms files, seems it ignores the second header information. Dunno about Winuae's dms handling....

If I do a utility I will limit it to two .dms files, only use track info to see if they are contiguous and don't overlap, and I won't interpret the track data at all, just form a new file with a (modified) single header.

I'll see if I can do it tonight... meanwhile, anyone see a problem with that method?

Hmm, might get trouble with unpacked/packed CRC, especially unpacked CRC since I don't want to unpack it... Is it a simple 16-bit sum, so I can add the words from the respective .dms files to join? But it's probably a "proper" CRC though, is it the 16-bit IBM CRC, or what flavor. Argh.

Codetapper is right. It's very easy, no tool coding needed. You can also use xdms to unpack both splitted dms files and then a simple copy /b later you have what you want...
Dms used the x^16+x^15+x^2+1 polynom as CRC-16 for the headers and for all tracks.

CodeTapper, Adderly, sure - but then I have to do that for every megademo I've downloaded from scene.org... As a programmer I like niftier solutions, if possible I mean, there are tons of split archives out there...

Quote:

Originally Posted by Adderly

Dms used the x^16+x^15+x^2+1 polynom as CRC-16 for the headers and for all tracks.

Right, so it's not possible to combine the checksums without interpreting the compressed or uncompressed data. Gah.